1. Field of the Invention
The present invention provides a displaying system, and more particularly, to a virtual image displaying system.
2. Descriptions of the Related Art
Over recent years, stereoscopic image displays have become a hot topic in research. The primary principle of stereoscopic image displays is as follows: a left-eye view-angle image and a right-eye view-angle image are fed by a display apparatus to the left eye and the right eye of a viewer respectively. Then, when the two images with the same image content but different parallaxes are viewed by both eyes of the viewer, depth will be perceived in the resulting image by the viewer because of the visual characteristics of the human eye. Thus, the resulting image is perceived as a stereoscopic image.
There are many technologies that can accomplish the aforesaid stereoscopic displaying principle, one of which is termed as the “time-multiplex autostereoscopic displaying system.”
With reference to FIG. 9, the so-called “time-multiplex autostereoscopic displaying system” was invented by Professor Adrian Travis of Cambridge University. The displaying system 9 has a cathode ray tube (CRT) display 91, two lenses 92 and a shutter or slit array 93.
The CRT 91 can project a light beam (i.e., an image), which then propagates through the lenses 92 to impinge on the slit array 93. The slit array 93 has a plurality of slits 931 which can be turned on sequentially rather than simultaneously. More specifically, at a certain time point, only one slit 931A among the slits 931 is turned on while the other slits 931B are all turned off.
Although the light beam impinges on all the slits 931 of the slit array 93, only a small part of the light beam can pass through the only slit 931A that is turned on while other parts of the light beam are blocked by the slits 931B that are turned off. The CRT 91 can adjust the intensity of the light beam projected by each pixel thereof (i.e., the CRT 91 can adjust the image displayed) according to the position of the slit 931A that is turned on. Therefore, as the slits 93 are turned on in sequence, each pixel of the CRT 91 will emit a light beam of different intensities and in different directions from the slit array 93.
By emitting light beams of different intensities and in different directions, the displaying system 9 can simulate light rays emitted by an object in a space to form a virtual image of the object that can be viewed by a viewer 94 in front of the slit array 93. In this sense, the time-multiplex autostereoscopic displaying system may also be termed as a “virtual image displaying system.”
The virtual image displaying system may be used in medical applications to allow medical workers to view stereoscopic images of patients' organs by means of the displaying system. The virtual image displaying system may also be used in a video call to allow both parties of the call to see each other's stereoscopic images.
However, the conventional virtual image displaying system has a bulky volume and occupies a large space, so the location where it is placed is limited and this makes it difficult to place it directly onto a desktop. Furthermore, if a large-size displaying frame is desired, the volume of the conventional virtual image displaying system must be increased significantly. For this reason, the conventional virtual image displaying system can only provide small-size displaying frames.
Accordingly, there is a need existed in the art to provide a virtual image displaying system that can overcome at least one of the aforesaid shortcomings.